Study of abnormalities of male sex differentiation: It includes subjects with XY karyotype (variant of androgen insensitivity syndrome with normal receptors, partial androgen insensitiviey, abnormal steroidogenesis and micropenis; (HY antigen); studies on human skin fibroblasts with antiandrogens and 5alpha-reductase inhibitors. Studies of patients with congenital adrenal hyperplasia: (a) long-term follow-up of male patients (plasma and urinary steroids, LH and FSH; sperm analysis and fertility; adult height). (b) several male patients with untreated adrenal hyperplasia will be particularly investigated (plasma steroids and gonadotropins, suppressibility of LH and FSH, response to LRH). (c) Studies of cortisol precursors in heterozygotes (parents and siblings of CVAH patients and so-called acquired CVAH). Studies of puberty: (a) Subunit fractions of LH and FSH in response to LRH in puberty. (b) Effects of FSH on testosterone production in normal adult males. (c) Effects of adrenal androgens on the hypothalamus and the start of puberty (male subjects with untreated adrenal hyperplasia or with Addison's disease). (d) Long-range follow-up of adolescent delay. (e) Gynecomastia in pubertal males and binding of estradiol to specimens removed at surgery. Studies involving human growth hormone: (a) Evaluation of 24 hr integrated concentration of growth hormone in short saturated children. (b) Evaluation of the effect of long-term exogenous growth hormone therapy in children with intrauterine growth retardation. (c) Evaluation of somatomedin levels in various growth disorders.